Electrically programmable fuse bit

ABSTRACT

One-time programmable (OTP) nonvolatile fuse memory cells are disclosed that do not require decoding or addressing for reading their data content. Each fuse memory cell has its content latched at its output and available at all times and can be used, for example, for code storage memories, serial configuration memories, and as individual fuse bits for ID (identification), trimming, and other post-fabrication System-on-Chip (SoC) customization needs. Means are also provided for temporary data storage for design testing, etc. In alternative embodiments, using two differentially programmed fuses in a single memory cell, the selection and programming circuitry are merged.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application is a divisional application of U.S. patent applicationSer. No. 11/699,916, filed Jan. 29, 2007, now U.S. Pat. No. 7,609,539which claims the benefit of U.S. Provisional Application No. 60/763,016,entitled “Electrically Programmable Fuse Bit,” filed Jan. 27, 2006, eachof which are incorporated herein by reference in their entireties.

TECHNICAL FIELD

The embodiments described below relate generally to the field ofone-time programmable (OTP) non-volatile memory cells and moreparticularly to CMOS implementation of a self-sensing non-volatile OTPfuse element.

BACKGROUND

Nonvolatile memory retains stored data when power is removed, which isdesirable in many different types of electronic devices. One commonlyavailable type of nonvolatile memory is the programmable read-onlymemory (“PROM”), which uses wordline-bitline crosspoint elements such asfuses, anti-fuses, and trapped charge devices such as the floating gateavalanche injection metal oxide semiconductor (“FAMOS”) transistor tostore logical information. The term “crosspoint” refers to theintersection of a bitline and a wordline.

An example of one type of PROM cell that uses the breakdown of a silicondioxide layer in a capacitor to store digital data is disclosed in U.S.Pat. No. 6,215,140 to Reisinger et al. The basic PROM disclosed byReisinger et al. uses a series combination of an oxide capacitor and ajunction diode as the crosspoint element. An intact capacitor representsthe logic value 0, and an electrically broken-down capacitor representsthe logic value 1. The thickness of the silicon dioxide layer isadjusted to obtain the desired operation specifications.

Improvements in the various processes used for fabricating the differenttypes of nonvolatile memory tend to lag improvements in widely usedprocesses such as the advanced CMOS logic process. For example,processes for flash EEPROM devices tend to use 30% more mask steps thanthe standard advanced CMOS logic processes. These processes are forproducing the special regions and structures required for the highvoltage generation circuits, the triple well, the floating gate, the ONOlayers, and the special source and drain junctions typically found insuch devices.

Accordingly, processes for flash devices tend to be one or twogenerations behind the standard advanced CMOS logic processes and about30% more expensive on a cost-per-wafer basis. As another example,processes for antifuses, which must be suitable for fabricating variousantifuse structures and high voltage circuits, also tend to be about onegeneration behind the standard advanced CMOS processes. These examplesindicate several disadvantages with the prior art memory technologies.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a prior art memory cell.

FIG. 2 illustrates a fuse memory cell, in accordance with an embodimentof the invention.

FIG. 3 illustrates a fuse memory cell with a high-voltage protectiontransistor, in accordance with another embodiment of the invention.

FIG. 4 is a high level block diagram of a 16-bit fuse-block using fusememory cells, in accordance with an alternative embodiment of theinvention.

FIG. 5A is a timing diagram for fuse programming of the fuse-block ofFIG. 4.

FIG. 5B is a timing diagram for sequential fuse programming for thefuse-block of FIG. 4.

FIG. 6 is a programming and verifying timing diagram for a fuse memorycell.

FIG. 7 is a SET and RESET timing diagram.

FIG. 8 illustrates an internal circuitry of a fuse memory cell.

FIG. 9 illustrates a differential fuse memory cell circuit, inaccordance with another embodiment of the invention.

FIG. 10 illustrates an alternative differential fuse memory cellcircuit, in accordance with yet another embodiment of the invention.

FIG. 11 shows source and drain details of fuse memory cell transistors.

FIGS. 12A and 12B illustrate two options for CMOS implementation of abasic fuse memory cell, in accordance with other embodiments of theinvention.

FIG. 13 illustrates another option for CMOS implementation of a basicfuse memory cell, in accordance with yet other embodiments of theinvention.

FIG. 14 illustrates an alternative variation of the circuit of FIG. 9.

FIG. 15 is a high level block diagram of an 18-bit fuse-block using fusememory cells, in accordance with an alternative embodiment of theinvention.

FIG. 16 illustrates the circuitry of the fuse-block of FIG. 15.

DETAILED DESCRIPTION

The embodiments explained in this description disclose one-timeprogrammable (OTP) nonvolatile fuse memory cells, which do not requiredecoding or addressing for reading their data content. The disclosedfuse memory cells occupy small areas and are optimized for low bit countapplications. Each fuse memory cell has its content latched at itsoutput, and available at all times. These memory cells can be used forcode storage memories, serial configuration memories, and as individualfuse bits for ID (identification), trimming, and other post-fabricationSystem-on-Chip (SoC) customization needs.

In general, to program one of these memory cells, a high voltage isapplied to a specific transistor of the memory cell to break down thetransistor (blow the fuse). For reading the fuse memory cell, thecurrent passing through the transistor is sensed. The current passingthrough the fuse is an indication of its data content, a “1” or a “0,”depending on the agreed convention.

The basic building block of the disclosed fuse memory cells is similarto the XPM memory cell of Kilopass Technologies, Inc. in Santa Clara,Calif., which is illustrated in FIG. 1. The fuse memory cell of FIG. 1includes a “select” transistor M1 and a programming transistor M0, bothof which can be fabricated using standard CMOS processes withoutadditional masking. In this memory cell, transistor M1 acts as a switchand M0 acts as a current limiter, wherein the current passing through M0is an indication of its programmed logic level (data content).

The gate of the programming transistor M0 acts as one plate of acapacitor and the application of the voltage to the gate causes aninversion layer to form under the gate which acts as the other plate ofthe capacitor, and together with the source/drain region forms thesecond terminal of the capacitor. Since it is undesirable to break downthe gate oxide of the select transistor M1, the gate oxide of the selecttransistor M1 may be made, in some embodiments, to have a thicker gateoxide than that of the programming transistor M0.

For programming the memory cell of FIG. 1, WLP is elevated to VPP (apredetermined high voltage), WLR is turned ON, and the BL is grounded,for a specified duration of time (e.g., 50 us), to break down the gateoxide of the programming transistor M0. This arrangement sets theleakage current level of the memory cell and, therefore, its logiclevel.

For reading the content of the memory cell, appropriate voltage(s) isapplied to the gates of M0 and M1 transistors, which connects M0 to thebit-line BL. Thereafter, to classify the logic level of the memory cell,the current passing through M1 and BL, which is limited by M0, is sensedby a sense amplifier.

Various embodiments of the invention will now be described. Thefollowing description provides specific details for a thoroughunderstanding and enabling description of these embodiments. One skilledin the art will understand, however, that the invention may be practicedwithout many of these details. Additionally, some well-known structuresor functions may not be shown or described in detail, so as to avoidunnecessarily obscuring the relevant description of the variousembodiments.

While the standard XPM memory cell, illustrated in FIG. 1, has nocontact on the node between the programming transistor M0 and the selecttransistor M1, the fuse memory cell, illustrated in FIG. 2, connects tothis node in order to provide a “self-sensing” voltage level. The“self-sensing” and the latching of the output of the fuse memory cellswill be discussed in more detail. This configuration does not require asense amplifier. In addition, the fuse memory cell may be designed usingstandard logic design rules. In the embodiment of FIG. 2, or in anyother disclosed embodiment, the programming transistor M0 may beconfigured to use the capacitance between its source and its gate, itsdrain and its gate, or its source and drain and its gate to implement afuse.

In FIG. 3, which illustrates a fuse memory cell with at least onehigh-voltage protection transistor M1, provides the cascade protectionfor the thin oxide M2 during the programming of the fuse transistor M0.In the circuit of FIG. 3, similar to the circuit of FIG. 2, the outputis taken from a point between M0 and M1 transistors.

The terminology used in the description presented below is intended tobe interpreted in its broadest reasonable manner, even though it isbeing used in conjunction with a detailed description of certainspecific embodiments of the invention. Certain terms may even beemphasized below; however, any terminology intended to be interpreted inany restricted manner will be overtly and specifically defined as suchin this Detailed Description section.

Multi-Bit Memory Implementations

In an exemplary multi-bit memory embodiment, the fuse circuit consistsof a cascadeable 16-bit fuse memory block (“fuse-block”), illustrated bythe high level diagram of FIG. 4. Each fuse-block has a PGM input pinthat is used to program the fuse memory cells of that particularfuse-block. Furthermore, to program the fuse memory cells of thefuse-block, each fuse-block has an addressing circuit that employs theA[3:0] input pins. The PGM input pin allows for the cascading ofmultiple fuse-blocks with the ability to program any fuse memory cellwithin any fuse-block. The 16 output pins of each fuse-block, REG[15:0],are the latched outputs of the 16 memory bits (fuse memory cells) of thefuse-block. While this example describes a 16-bit fuse memory block,other data word widths (e.g. 1, 4, 8, 32, etc.) are extensions of thisexample.

Fuse Memory Block Programming Operation

The fuse memory block is programmed one fuse memory cell at a time bypulsing the “PGM” and VPP pins for t_(PGM) seconds (e.g., 50 μSec) whileasserting the selected fuse address on the A[3:0] pins and the blockselect pin BS, which enables operational access to a single fuse of thefuse-block. Note that, physically, programming a memory cell meansblowing its fuse or breaking down a particular transistor. The VPP pinalso provides the actual per-fuse programming timing, while the PGM pinhas setup and hold requirements that depend on the VPP voltage values.An example of the VPP voltages for different process nodes is depictedin Table 1 and the corresponding program timing diagrams are illustratedby FIG. 5A. Using these program timings makes it possible to programseveral fuse memory cells sequentially, as shown in FIG. 5B.

TABLE 1 VPP vs. Process Node Node VPP 0.35 μm  16 v 0.25 μm  13 V 0.18μm 8.5 V 0.15 μm 7.5 V 0.13 μm 6.5 V 90 nm 6.0 V

Program Verifying Operation

While it may not be possible to directly read a memory fuse cell outputduring a programming process, it may be desirable to test a fuse memorycell to make sure it has been properly programmed. In such a case, amethod is needed to verify whether the memory cell fuse has beenproperly blown or not. Therefore, after programming, the current(I_(READ)) into the fuse is monitored to determine whether or not theprogramming was successful. For this purpose, a tester such as thewafer-level testers may be employed.

Because, in this example, there is no dedicated verify-mode-pin, the VPPpin is used at a lower voltage, as follows:

VPP Pin≧VPP voltage (see Table 1): Program Mode

VPP Pin≧VDDIO but≦VPP voltage: Verify Mode

VPP Pin=VDDIO: Fuse Read Mode (Normal Operation)

FIG. 6 illustrates a timing diagram for a PGM/Verify cycle of fuse “0,”which is the fuse addressed by A[3:0]=A0. Thus, the current that isdrawn into the VPP Pin, and that passes through the programmedtransistor M0, is measured to determine if in fact the fuse memory cellhas been programmed as desired.

SET and RESET Operations

It may be desirable, for example during prototyping or programverification, to temporarily program a fuse memory cell without blowingits fuse. The SET and RESET lines available in some embodiments of thefuse-block allow temporarily storing data into a fuse memory cell latchwithout permanently programming its fuse, and making the data availableat the memory cell's output. The fuse memory block allows individual SETand RESET options of each fuse memory cell latch to be used for testingof functionality and to override the latch content. The required timingis shown in FIG. 7.

FIG. 8 depicts, in greater detail, an example of the latching of theoutput of fuse M0 by two cross-coupled NAND-gates A1 and A2, and thepossibility of manipulating the latch by the SET and RESET signals.

Fuse Memory Cell Circuit Details

FIG. 8 illustrates the circuitry of an embodiment of a fuse memory cell.In the circuit of FIG. 8, an individual fuse M0 is selected by thecombination of the address pins A[3:0], BS, and PGM for programming orverifying. The fuse which has been selected for programming or verifyinghas its high voltage supplied by the VPP pin after passing through anoptional high-voltage level shifter circuit X6. The high-voltage levelshifter X6 is provided to isolate a non-accessed fuse from theprogramming voltage when a different fuse in the same block is beingprogrammed. Alternate embodiments of the invention omit the levelshifter, as will be discussed below. In an alternative embodiment ofthis circuitry, the three-transistor memory cell is replaced by thetwo-transistor memory cell of FIG. 2.

FIG. 8 also illustrate the “self sensing” attribute of the disclosedembodiments, where the content of fuse M0 is latched at the output bythe cross-coupled NAND-gates A1 and A2. When the fuse is programmed, thecorresponding output value (REG) is static and does not need to bedynamically sensed.

Differential Fuse Circuits

In an alternative embodiment, by using two differentially programmedfuses in a single memory cell, it is possible to merge the selection andprogramming circuitry of FIG. 8. In addition, capacitors C1 and C2 canbe eliminated, because differentially programmed fuse memory cells willalways power up the latch to a valid state. FIG. 9 shows a circuitdiagram of a differential fuse memory cell using the memory core shownin FIG. 1.

In this implementation a “SET” operation (i.e. SET=0) on anun-programmed fuse memory cell will result in a “Q” output of logic “0”after a program operation, and a “RESET” operation (i.e. RST=0) on anun-programmed fuse memory cell will result in a “Q” output of logic “1”after a program operation.

The alternative embodiment of FIG. 10 uses PMOS transistors as fuseelements (M6 and M7) rather than NMOS transistors. This constructionovercomes the SET/RESET behavior of the embodiment depicted in FIG. 9.This alternative embodiment also provides the ability to keep the highvoltage external to the low-voltage transistors via M6 and M7 devices.In this embodiment the VPP is applied to the source and drain, not tothe gate, and therefore no isolation devices, such as M2 and M3 of FIG.9, are necessary.

FIG. 14 illustrates an alternative variation of the circuit of FIG. 9.In FIG. 14 the flop (mirror image circuit) consisting of P0, P1, P2, P3,N4, N5, N6, N7, is set or reset by setb or rstb lines, which isreflected at Q and QB outputs. Utilizing the set and reset options, auser can evaluate if a particular logic level is what the user wants,and can subsequently make it permanent by programming the circuit.

Suppose the flop is set so that Q=1, and QB=0. Then P3=0, and P0=1, seland pgm are 1, pgmb is 0, and vpr is bias. Then VPP is elevated to it'shighest voltage. The fuse oxide is ruptured and current flows throughN21, N11, N18 (because P0=1), and N36 (which is the currentlimiter—there is a window of current for best programming). There is nopath to ground for the other fuse, so it cannot be programmed andthereby has a high impedance. The programmed fuse has a much lowerimpedance.

Another advantage of this circuit is that, after it is programmed, italways comes up in the correct state during subsequent power ups. Thisis because the programmed fuse unbalances the flop and pulls up theprogrammed fuse side of the flop.

High-Voltage Tolerant Circuit

In the circuit of FIG. 8, a high-voltage level shifter X6 is provided toisolate a non-accessed fuse from the programming voltage when adifferent fuse in the same block is being programmed. This isolation isnecessary due to the possibility of junction breakdown in thesource/drain of the fuse transistor M0. Should the junction breakdownoccur, it can provide a preferential path for excessive current flow toground, which would cause poor cell characteristics. It can also causeexcessive current drawn from the VPP supply when VPP is applied to asignificant number of fuse transistors already programmed (i.e.conducting bits).

If the source/drain junction of the fuse transistor M0 or of the selecttransistor M1 breaks down at a voltage equal to or below that of theoxide of M0, the mentioned situation will occur and undesired currentwill flow from VPP to ground via P-N Junction diodes D2 and D0 in FIG.11, where D0 and D2 represent the drain and source diffusions,respectively, of transistor M0. And, diode D3 represents the draindiffusion of transistor M1. Each of these diodes has a breakdown voltageBV_(J) (maximum reverse diode potential). If BV_(J) of any of thesediodes is equal to or less than BV_(OX) (oxide breakdown voltage) of M0,VPP must be restricted to a small number of fuse transistors or thecurrent from junction breakdown can exceed the maximum current capacityof the VPP supply. The solution is to increase the BV_(J) of diodes D0,D2 and D3. To increase the BV_(J) of diodes D0, D2 and D3, two methodsare described below.

NWELL Junction Implant

In two embodiments of this method, as shown in FIGS. 12A and 12B, N-typewell implants, which are the same implants used for a standard PMOStransistor body, are co-implanted with the N+ Source/Drain implant. Thiscreates a graded junction due to the presence of the NWELL implant. Themethod of FIG. 12B (NWELL under the poly) is an acceptable solution forthis application because transistor action of M0 is not required. Thisclass of solutions requires no extra masks or process steps, andincreases the breakdown voltage of diodes D0, D2, and D3 toapproximately 18V (in 0.18 μm CMOS process), which is much higher thanBV_(OX) of M0 and satisfies the desired criteria.

“NATIVE” Junction

FIG. 13 illustrates another option for CMOS implementation of a basicfuse memory cell, in accordance with yet other embodiments of theinvention. In this method transistors M0 and M1 are made “Native”, thatis, the VT (VT is ‘0 ’ or slightly negative) adjustment implant (PWELL)is blocked during processing. Again, no additional masking or processingsteps beyond conventional CMOS is necessary. This procedure creates a Pregion beneath the transistor with a lower concentration than thestandard P-Substrate, and therefore a higher BV_(J).

Fuse-Block

In another exemplary multi-bit memory embodiment, the fuse circuitconsists of a cascadeable 8-bit fuse memory block (“fuse-block”),illustrated by the high level diagram of FIG. 15. Each illustratedfuse-block, like the fuse block shown in FIG. 4, has a pgm input pinthat is used to program the fuse memory cells of that particularfuse-block. Furthermore, to program the fuse memory cells of thefuse-block, each fuse-block has an addressing circuit that employs thea[3:0] input pins. The pgm input pin allows for the cascading ofmultiple fuse-blocks with the ability to program any fuse memory cellwithin any fuse-block. The 8 output pins of each fuse-block, reg[7:0],are the latched outputs of the 8 memory bits (fuse memory cells) of thefuse-block. The purpose of the other pins shown in FIG. 15 will bediscussed in detail when describing the inner circuitry of this shown inFIG. 15 will be discussed in detail when describing the inner circuitryof this fuse block which is illustrated by FIG. 16. While this exampledescribes an 8-bit fuse memory block, other data word widths areextensions of this example.

FIG. 16 illustrates the circuitry of another embodiment of a fuse memorycell used in the fuse-block of FIG. 15. In the circuit of FIG. 16, anindividual fuse XX is selected by a combination of the address pinsa[3:0], bs, and pgm for programming or verifying. In one embodiment thefuse is a device such as a transistor. The fuse which has been selectedfor programming or verifying has its high voltage supplied by the “bias”input pin. In an alternative embodiment of this circuitry, thethree-device memory cell MC is replaced by the two-transistor memorycell of FIG. 2.

The programming process occurs when (1) node “sel” is high, which groundnode “src,” (2) signal pgm is high (about 3.3v), and (3) signal “bias”is high (about 8.5v). This arrangement programs the fuse XX, wherein theprogrammed current will be limited by the impedance of device N12.

The read process for this circuit starts with a positive edge “bs”signal, which, among other things, enters the “pulgenb” block andcreates a short width Vdd level signal called “dump.” The dump signaldischarges any leakage-buildup on node “fus” and resets the latchcreated by the two NAND-gates. Using the negative edge of dump signal,block pulgenb generates a wider Vdd level pulse “eval,” which evaluatesthe voltage on node fus and sets the latch if fus is “1.” eval is wideenough for mode fus so that there is enough time for fus to again chargeup if fus has been programmed. Signal “leak” provides a small positivevoltage to turn ON device N14 and ensure that node fus is clamped toground when the fuse is not programmed.

Signal “bias” provides a high voltage for programming when input signalpgm is high and a lower voltage for reading when pgm is low. Block 1501level shifts from Vdd (1.8v) to 3.3v when pgm is high and to 0v when pgmis low or signal vdd is low. Block 1503 outputs 8.5v if signal pgmhi islow and 1.8v if pgmhi is high.

Devices N0 and N4, which act as two series gates between the memory fuseand the memory cell latch, are intrinsic or native to reduce thresholddrop from node “fuse” to node “fus.” Device N7 is provided to cove acase where programming process has started but no cell has been selectedyet. In alternative embodiments of the memory circuit of FIG. 16, someof the transistors and their functions may be omitted.

CONCLUSION

Unless the context clearly requires otherwise, throughout thedescription and the claims, the words “comprise,” “comprising,” and thelike are to be construed in an inclusive sense, as opposed to anexclusive or exhaustive sense; that is to say, in the sense of“including, but not limited to.” As used herein, the terms “connected,”“coupled,” or any variant thereof, means any connection or coupling,either direct or indirect, between two or more elements; the coupling ofconnection between the elements can be physical, logical, or acombination thereof.

Additionally, the words “herein,” “above,” “below,” and words of similarimport, when used in this application, shall refer to this applicationas a whole and not to any particular portions of this application. Wherethe context permits, words in the above Detailed Description using thesingular or plural number may also include the plural or singular numberrespectively. The word “or,” in reference to a list of two or moreitems, covers all of the following interpretations of the word: any ofthe items in the list, all of the items in the list, and any combinationof the items in the list.

The above detailed description of embodiments of the invention is notintended to be exhaustive or to limit the invention to the precise formdisclosed above. While specific embodiments of, and examples for, theinvention are described above for illustrative purposes, variousequivalent modifications are possible within the scope of the invention,as those skilled in the relevant art will recognize.

Changes can be made to the invention in light of the above DetailedDescription. While the above description describes certain embodimentsof the invention, and describes the best mode contemplated, no matterhow detailed the above appears in text, the invention can be practicedin many ways. Details of the compensation system described above mayvary considerably in its implementation details, while still beingencompassed by the invention disclosed herein.

As noted above, particular terminology used when describing certainfeatures or aspects of the invention should not be taken to imply thatthe terminology is being redefined herein to be restricted to anyspecific characteristics, features, or aspects of the invention withwhich that terminology is associated. In general, the terms used in thefollowing claims should not be construed to limit the invention to thespecific embodiments disclosed in the specification, unless the aboveDetailed Description section explicitly defines such terms. Accordingly,the actual scope of the invention encompasses not only the disclosedembodiments, but also all equivalent ways of practicing or implementingthe invention under the claims.

All of the above patents and applications and other references,including any that may be listed in accompanying filing papers, areincorporated herein by reference. Aspects of the invention can bemodified, if necessary, to employ the systems, functions, and conceptsof the various references described above to provide yet furtherembodiments of the invention.

While certain aspects of the invention are presented below in certainclaim forms, the inventors contemplate the various aspects of theinvention in any number of claim forms. Accordingly, the inventorsreserve the right to add additional claims after filing the applicationto pursue such additional claim forms for other aspects of the invention

1. A programmable read only memory circuit configured to be a part of amulti-bit memory block, the memory circuit comprising: a single-bit corememory cell comprising at least a select device, a high-voltageprotection device, and a fuse device in series, wherein data isprogrammed in the cell through permanently altering at least onephysical characteristic of the fuse device by turning on the selectdevice and applying a controlled high voltage to the gate of the fusedevice for a predetermined period of time; a single-bit latch forlatching an output of the single-bit core memory cell or an externallyprovided data bit; a set and a reset input line for controlling thesingle-bit latch content; a block-select input line for selecting amemory block among a plurality of memory blocks; multiple address inputlines for selecting a memory circuit among a plurality of memorycircuits of a memory block; and a programming input line for enablingprogramming of memory circuits of a selected memory block.
 2. The memorycircuit of claim 1, wherein the single-bit latch is essentiallyimplemented by two cross-coupled NAND-gates.
 3. The memory circuit ofclaim 2, wherein the fuse data passes at least through one transistor onthe way to the single-bit latch, and wherein a signal at the transistorgate control the passage of the data.
 4. The memory circuit of claim 2,wherein an input of the single-bit latch is connected to ground throughtwo series transistor, wherein gate of one of the two series transistorsis controlled by the fuse data.
 5. The memory circuit of claim 4,wherein the transistor gate controlled by the fuse data is connected toground by at least one leakage control transistor.
 6. The memory circuitof claim 1, wherein the fuse device is a transistor, and whereinaltering at least one physical characteristic of the fuse transistor isby breaking down dielectric or gate oxide of the fuse transistor.
 7. Thememory circuit of claim 1, wherein in a CMOS implementation of the corememory cell, N-type well implants are co-implanted with the N+Source/Drain implant creating a graded junction due to the presence ofthe NWELL implant.
 8. The memory circuit of claim 1, wherein in CMOSimplementation of the core memory cell, the fuse and the select devicesare “Native.”
 9. The memory circuit of claim 1, wherein the memorycircuit is temporarily programmed, without breaking down the fusedevice, by using the set and the reset input lines to temporarily storedata into the single-bit latch.
 10. The memory circuit of claim 1,wherein an individual memory circuit is selected for programming orverifying by a combination of address input lines, the block-selectinput line, and the programming input line.
 11. A one-time programmablememory circuit comprising: a single-bit core memory means for storing asingle data bit, wherein the data bit is programmed in the memory meansby permanently altering capacitance of a fuse device; a single-bit latchmeans for latching an output of the single-bit core memory means orlatching an externally provided data bit, wherein: the single-bit latchis implemented by two cross-coupled NAND-gates; the fuse data isconnected to the single-bit latch through at least one transistor and asignal at the transistor gate controls the fuse data passage; and aninput of the single-bit latch is connected to ground through at leastone transistor, a gate of which is controlled by the fuse data and isalso connected to ground by at least one leakage control transistor; aset and a reset means for controlling the single-bit latch content; ablock-select input means for selecting a block of multiple memorycircuits among a plurality of memory circuit blocks; multiple addressinput means for selecting a memory circuit among multiple memorycircuits of a memory circuit block; and a programming input means forenabling programming of memory circuits of a selected memory circuitblock.